Good point!.....I usually do square apertures on BGAs below 16 mil pad
size, but in this case I was afraid the joints would bridge if the ball
size increases due to voiding. I will have to try the square apertures
and see.
Thanks,
Amol
-----Original Message-----
From: Bush, Brien [mailto:[log in to unmask]]
Sent: Thursday, August 16, 2012 11:32 AM
To: 'TechNet E-Mail Forum'; Amol Kane (Asteelflash,US)
Subject: RE: CSP BGAs
What type of paste are you using? We are processing a bga 1x.8 with a .5
pitch and .175 ball diameter. We are using a Kester lead free EM828
solder paste. We have the stencil Apertures cut square encompassing the
round pad. This allows for slightly more paste.
Hope this helps,
Brien
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Amol Kane
(Asteelflash,US)
Sent: Thursday, August 16, 2012 9:34 AM
To: [log in to unmask]
Subject: [TN] CSP BGAs
Dear Technetters,
We are going to be assembling some lead-free 1.6x0.8 mm micro BGAs with
0.5mm pitch and 0.17mm dia board pads. Anybody else have experience with
this small a package?....I am concerned that there won't be sufficient
flux in the tiny solder deposit to clean the oxides during reflow,
leading to graping and/or head in pillow situation. Do I need a dip
fluxer for the part to do a flux only attachment, or to augment the
amount of flux in the solderpaste-solder bump system? I am told I have
no time to do DOEs to determine stencil and reflow parameters, so I am
turning to technet for help.....any thoughts?
Regards,
Amol
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